Actually, it began a long time ago: In December '06, Ben Rockwood wrote about the beauty of ZFS and iSCSI integration, and immediatley I thought "That's the perfect solution to back up my Mac OS X PowerBook!" No more strings attached, just back up over WLAN to a really good storage device that lives on Solaris ZFS, while still using the Mac OS X native file system peculiarities. But Apple didn't have an iSCSI initiator yet (they still don't have one now) and the only free iSCSI initiator I could find was buggy, unstable and didn't like Solaris targets at all.

Then, Apple announced their Time Machine technology. Many people thought that this was related to them supporting ZFS and in fact, it's easy to believe that Time Machine's travels back in time are supported by ZFS snapshots. But they aren't. In reality, it's just a clever use of hardlinks. And not a very efficient one, too: Whenever a file changes, the whole file gets backed up again, even if you just changed a little bit of it.

They have both been shared as iSCSI targets through a single zfs set shareiscsi=on santiago/volumes command, thanks to ZFS' attribute inheritance:

-bash-3.2$ zfs get shareiscsi santiago/volumes

NAME PROPERTY VALUE SOURCE

santiago/volumes shareiscsi on local

-bash-3.2$ zfs get shareiscsi santiago/volumes/aperturevault

NAME PROPERTY VALUE SOURCE

santiago/volumes/aperturevault shareiscsi on inherited from santiago/volumes

-bash-3.2$ zfs get shareiscsi santiago/volumes/mbptm

NAME PROPERTY VALUE SOURCE

santiago/volumes/mbptm shareiscsi on inherited from santiago/volumes

-bash-3.2$

On the Mac side, they show up in the globalSAN GUI just nicely:

And Disk Utility can format them perfectly as if they were real disks:

Time Machine happily accepted one of the iSCSI disks and synced more than 190GB to it just fine and as I type these lines, Aperture is busy syncing more than 40GB of photos to the other iSCSI disk (it wouldn't accept a network share). Sometimes, they're busy working simultaneously :).

Of course, iSCSI performance heavily depends on network performance, so for larger transfers, a cable connection is mandatory. But the occasional Time Machine or Aperture sync in the background runs just fine over WLAN.

So finally, Solaris and Mac fans can have a Time Machine based on ZFS, with real data integrity, redundancy, robustness, two different ways of travelling through time (ZVOLs can be snapshotted just like regular ZFS file systems) and much more.

Many thanks to Christiano for letting me know and to the guys at Studio Network Solutions for making this possible. And of course to the ZFS team for a wonderful piece of open storage software!

Thursday Nov 01, 2007

This article helps you deal more efficiently with large amounts of email. It looks at client and server side features that are useful, then concentrates on the most crucial aspect of email efficiency: Email processing workflow. We'll develop 7 easy to follow rules that will enable us to reach 0 mails in our Inbox in a short time while still staying informed earlier, easier and more reliably.[Read More]